A fourth sequel, Galaga '88, was released in 1987, and imported to North America by Atari Games and a fifth and final sequel, Galaga Arrangement, was released as part of the Namco Classic Collection Vol. However, by 1984 the novelty of the Space Invaders formula had faded, and it was no longer successful. As with Galaga, this was a fixed shooter, with limited vertical movement (like Centipede). A third official sequel, Gaplus, was released in 1984. The most popular of these was its immediate successor, Galaga, which largely eclipsed its predecessor in popularity, introducing aliens attacking in intricate formations, multiple shots, and bonus stages. Galaxian has spawned several follow-up games. Famicom Tsūshin in 1995 scored the Game Boy version of the game a 24 out of 40. Softline in 1983 criticized the Atari 8-bit version of the game for being shipped on cartridge, which raised its cost, and stated that "this game becomes tedious very quickly". Home Computing Weekly in 1983 gave the Spectrum version of Galaxian 3/5 stars describing it as a well-written version and praising the graphics as fast although flickery. The Astrocade version would later be awarded a Certificate of Merit for "Best Arcade-to-Home Video Game Translation" at the 4th annual Arkie Awards.:108 Arcade Express reviewed the Atari 5200 version in November 1982 and scored it 7 out of 10.
Video magazine in 1982 reviewed the Astrocade version of Galaxian (named Galactic Invasion), noting that the graphics were inferior to the coin-op and PC versions, but praising the play-action as "magnificent" compared to other console versions. Midway had previously published Space Invaders in the market, but had to seek new foreign partners when Taito decided to market their games themselves. Soon after the Japanese release Namco partnered with the American company Midway to release the game in North America. The result was more complex and difficult game play.
Unlike Space Invaders, which was black and white and featured enemies that could only move vertically and horizontally as they descended, Galaxian had a color screen and enemies that descended in patterns and came from various directions. Galaxian incorporated new technology into its dedicated arcade system board, the Namco Galaxian. It was designed to build and improve upon the formula of Taito's game Space Invaders, which revolutionized the gaming industry upon its release a year earlier. The game was developed by Namco in 1979, and released in Japan that year. A plain and repetitive starfield scrolls in the background. The player defeats one swarm, only to have it replaced by another more aggressive and challenging swarm in the next stage. The ship can only have one shot on screen at a time. Swarm after swarm of alien armies attack the player's ship that moves left and right at the bottom of the wraparound screen. It also features a crude theme song and more prominent background "music." These elements combine to create a look and feel that would set the standard for arcade games in the 1980s such as Pac-Man. Although not the first color video game, Galaxian took RGB color graphics a step further with multi-colored animated sprites and explosions, different colored fonts for the score and high score, the scrolling starfield, and graphic icons that show the number of lives left and how many stages the player had completed. Galaxian was very successful for Namco and introduced several "firsts". The game's plot consists of a title screen that displayed the message "WE ARE THE GALAXIANS / MISSION: DESTROY ALIENS". This made it the first game to feature enemies with individual personalities. In contrast to Space Invaders, Galaxian added an element of drama by having the aliens periodically make kamikaze-like dives at the player's ship, the Galaxip.
As in the earlier game, Galaxian features a horde of attacking aliens that exchanged shots with the player. Galaxian expanded on the formula pioneered by Space Invaders.